System for providing power to a maritime vessel

ABSTRACT

A drive system mounted to the hull of a buoyant vessel, the drive system having a rectifier, a generator, an AC bus in communication with shore power or a charging system and the rectifier, a DC bus in communication with the rectifier, at least one energy storage system, an inverter, a prime mover, a load regenerating device, and a control and monitor system which has predefined specifications for at least one of: storage units of at least one energy storage system; stored therein and wherein the control and monitor system is adapted to: automatically control the DC/DC converters, relieve a current draw from one or more storage units, provide charging current, and automatically draw power and redirect energy.

RELATED APPLICATION

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 16/386,049 filed on Apr. 16, 2019. U.S.patent application Ser. No. 16/386,049 is a continuation of U.S. patentapplication Ser. No. 12/313,732, filed on Nov. 24, 2008, which claimspriority to U.S. Provisional Patent Application Ser. No. 61/004,397,filed on Nov. 25, 2007. The referenced are hereby incorporated in theirentirety.

FIELD

The present embodiment generally relates to a system for providing powerto a marine vessel. Still more particularly, the present inventiondiscloses a method and apparatus wherein, depending on the mode ofoperation, a combination of batteries, and/or other stored energyresources and engines provides power to a marine vessel such as atugboat, a ferry boat, or an offshore service vessel.

BACKGROUND

A need exists for a carbon reducing drive system.

The present embodiments meet these needs.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description will be better understood in conjunction withthe accompanying drawings as follows:

FIG. 1 depicts a side view of a buoyant vessel with a drive systemaccording to an embodiment.

FIG. 2 is a schematic illustrating the major functional systems of thedrive system of the present invention.

FIG. 3 depicts a detailed schematic of the functional systems shown inFIG. 1.

FIG. 4 depicts a schematic illustrating the controls of the drive systemof FIG. 2.

The present embodiments are detailed below with reference to the listedFigures.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Before explaining the present drive system in detail, it is to beunderstood that the drive system is not limited to the particularembodiments and that it can be practiced or carried out in various ways.

Specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a basis of the claims and as arepresentative basis for teaching persons having ordinary skill in theart to variously employ the present invention.

Buoyant vessels, can be marine vessels such as tugboats and ferry boats.A tugboat, or tug, is a boat used to maneuver, primarily by towing orpushing, other marine vessels in harbors, over the open sea or throughrivers and canals. They are also used to tow barges, disabled ships, orother equipment like tow boats. Further, they are used to extinguishfires in water locations where land equipment cannot performfirefighting operations.

Presently, marine vessels, such as ferry boats and tugboats are poweredby diesel engines. One disadvantage of diesel engines is that dieselengines emit a large amount of pollutants including compounds thatcontain carbon such as carbon dioxide.

Another disadvantage is that diesel engines consume a large amount offuel while performing routine tug boat operations. Another disadvantageis that the use of diesel engines requires a large space for the drivelines in the tugboat. Still another disadvantage is that diesel enginesare very noisy and contribute to elevated levels of noise pollution. Thepresent invention overcomes these disadvantages.

The present invention relates to a drive system to power a buoyantvessel, such as a tugboat, wherein the drive system utilizes an ESScombination of stored energy batteries, sored energy battery/capacitorsand generators. The generators are only used in the towing mode, thatis, when the tugboat is attached to a barge or when charging thebatteries. Other modes of operation the buoyant vessel can operateentirely from ESS (stored energy).

The use of stored energy ESS dramatically reduces carbon emission whilemeeting or exceeding the functionality, safety and power requirements ofpresent day marine vessels, including tugs. Such carbon emissionreduction can be as high as 90 percent when compared to the presentpower drive designs. Further the use of stored energy ESS substantiallyreduces power consumption, the drive line space requirements and thenoise level.

The present invention relates to a drive system having a port sectionand/or a starboard section.

The port section and the starboard section may be operated independentlyor may be cross connected at several points, as needed. Components ofthe port section are similar to the components of the starboard section.

The port section and the starboard section each include a diesel engineand generator, an optional AC bus, a rectifier, a battery bank, a DC busand inverters that drive the motors in the buoyant vessel, a shore powerconnection and a fire pump motor.

The AC bus is connected to the generator and the shore power connectionto receive electrical power therefrom.

The fire pump motor is connected to receive electric power directly fromthe generator when activated. The fire pump motor can also receive powerfrom a shore power source.

The generator provides a variable voltage that can range from 10% underto 10% over a rated voltage and the generator is normally connected tothe rectifier.

The generator prime mover (such as diesel engine) can operate in thevariable frequency mode to optimize the KW loading on the prime mover.

The rectifier converts alternating current from the AC bus to directcurrent which is supplied to the DC bus.

The DC voltage from the rectifiers is used by the ESS for recharging andby the inverters to drive the motors loads.

The ESS is bi-directionally connected to the DC bus to receive chargingcurrent from the generator and other sources and to provide power to theDC bus which in turn powers the DC to AC inverters.

The inverters are capable of handling regenerated power which isregenerated under certain conditions, such as power generated by a winchwhen a load is dropping and power generated by a thruster when rotationis reversed or energy is harvested from the vessel hull when the buoyantvessel slows down.

Smaller amounts of power may also be regenerated from the steering gearor from the use of a thruster.

The batteries in the battery bank are connected to automatically absorbregenerated power, either by displacing load current or by discharging.If the voltage in the DC bus reaches a certain level, namely, about 750volts (as adjusted for ESS battery temperature) a chopper diverts theexcess regenerated power to an air cooled grid resistor. Shore poweravailable from the AC bus can also be used to charge the batteries ofthe battery bank through an inverter. A redundant control system isprovided for each port and starboard section.

The drive system is designed to operate in three different modes,namely, the green mode, the tow mode and the firefighting mode.

Green mode is the default mode of operation. In the green mode thevessel is supplied power only by the ESS energy banks without utilizingthe diesel engines for ship propulsion and/or ship service. The controlsystem energizes generators only when needed to provide peak power orESS charging. The ESS banks hold enough energy to sustain incidentalloads for over 8 hours between charges; however ESS energy life isincreased when more shallow discharge cycles are used. The generatorscome on line automatically based on a combination of the load and theESS state of charge. In the green mode, the minimal use of dieselengines cause substantial reduction in noise level, energy consumptionand carbon emissions. Green mode is designed for operating the vesselbetween locations when it is not towing another vessel and for docksideoperations.

The tow mode may be manually selected by the operator. Selecting towmode energizes the diesel engines and generators so that power will beavailable immediately to support peak power demands. The voltage fromthe generators maintains a float charge on the ESS banks except at veryheavy loads, where power is drawn from the ESS banks to supplement thegenerators. The diesel engine RPMs are adjusted to maintain optimal KWloading on the diesel engines.

The firefighting mode may be manually selected by the operator.Firefighting mode energizes diesel engines and generatorssimultaneously, and gives priority to the fire pumps that are driven bythe fire pump motors.

The use of the combination of ESS banks and generators allows forreduction of use of generators in certain operating modes and, moreparticularly, in the green mode.

Generators are only used in the towing mode, firefighting mode or whencharging the ESS storage. As a result, fuel consumption is reduced,lowering fuel costs and simultaneously lowering carbon emissions fromthe buoyant vessel. The replacement of diesel engines and generatorswith ESS banks reduces the size of the drive line and the overall spacerequired for the system within the hull.

Identical interchangeable modules are used in the inverters.Interchangeable modules are automatically reprogrammed andinterchangeable modules can be replaced at sea quickly thereby reducingdown time and maintenance costs.

The novel drive system can be mounted to the hull for balancing powerbetween electrical devices on a buoyant vessel using a digital signalprocessor that enables a particular module to respond instantly andcorrectly to changing voltages, currents, temperatures, thrusters andpropellers of the buoyant vessel.

The drive system includes a rectifier for converting AC current to DCcurrent.

The drive system includes a generator connected to the rectifier.

The drive system includes an AC bus in communication the rectifier.

The drive system includes a DC bus in communication with the rectifier.

The drive system includes a DC/DC converter in communication with the DCbus and the ESS

The drive system includes at least one ESS energy storage system with atleast one storage unit in bi-directional communication with the DC/DCconverter; wherein the DC/DC converter selectively controlsbidirectional charging and discharging of the at least one ESS energystorage system.

The drive system includes an inverter in communication with the DC bus.

The drive system can power a prime mover; using a load regeneratingdevice connected to the inverter. A rectifier can be configured toprovide regenerated power from the prime mover, load regeneratingdevice, or combinations thereof to the energy storage system; and acontrol and monitor system can be used in communication with the DC/DCconverter, one or more storage units of the at least one energy storagesystem, and the generator.

The control and monitor system has predefined specifications for atleast one of: storage units of at least one ESS energy storage system;stored therein, and wherein the control and monitor system is adaptedto: a. automatically control the DC/DC converter when one or morestorage units of an ESS energy storage system or one of the energystorage systems falls below a predetermined load, or the charge level ofone or more of the storage units of an ESS energy storage system or oneof the energy storage systems is depleted past a preset limit of thecharge level thereof; b. automatically relieve a current draw from oneor more storage units of an ESS energy storage system or one of theenergy storage systems; c. automatically provide charging current to theone or more storage units of an energy storage system or one of the ESSenergy storage systems; and d. automatically draw power from at leastone of the load regenerating device and the generator, and redirectenergy from at least one of the load regenerating device and thegenerator to the DC/DC converter and then to one or more storage unitsof an energy storage system or to an energy storage systems.

The ESS storage system includes at least one of: a battery, abattery-ultra capacitor, an ultracapacitor, and capacitors.

In embodiments, the control and monitor system has predefinedspecifications for at least one of: storage units of at least one ESSenergy storage system, and at least one ESS energy storage system;stored therein and wherein the control and monitor system is adapted to:monitor at least one of: the storage units of at least one energystorage system and the energy storage system and to automatically startthe prime mover.

In embodiments, the control and monitor system has predefinedspecifications for at least one of: storage units of at least ESS oneenergy storage system, and at least one energy storage system; storedtherein and wherein the control and monitor system is adapted to:control the DC to DC converters to ensure one or more storage units ofan ESS energy-storage system or one or more ESS energy storage systemsare not overcharged.

In embodiments, a plurality of voltage sensors are used for scaledvoltage feedback of the monitored energy storage units or systems whenone or more storage units of an energy storage system or one of theenergy storage systems voltage is reduced below preset level and aplurality of temperature sensors are used for determining temperature ofthe ESS energy storage units.

In embodiments, the control monitor system reads the plurality ofvoltage sensors, the plurality of temperature sensors, the thruster loadand the propeller load.

In embodiments, the control and monitor system is configured to monitorand control the DC/DC converter levels to control a charging rate of theone or more storage units of an ESS energy storage system or one of theESS energy storage systems.

In embodiments, the load regenerating device is a winch motor, steeringmotors, thruster motors, propeller motor, fire pump motors, motorcontrol centers, or combinations thereof.

In embodiments, the control and monitor system prevents generatorexcitation levels from exceeding a maximum excitation level of the DCbus.

In embodiments, the DC bus in communication with the rectifier is atleast one: a split DC bus or a non-split DC bus.

In embodiments, the from 2 to 10 DC bus can be used.

In embodiments, the ESS energy storage system has a chopper connected toa resistor for dissipating excess power if one or more storage units orone or more ESS energy storage systems are offline or full of power.

In embodiments, from 1 inverter to 50 inverters.

In embodiments, the control and monitor system comprises a communicationnetwork.

In embodiments, the communication network is at least one of: a globalcommunication network, a local communication network, a cellularcommunication network, the internet, and a satellite communicationnetwork.

In embodiments, the generator and the prime mover can be variable speed,and wherein the generator is variable voltage to control fuelefficiency.

In embodiments, each AC/DC bus is in electrical communication with shorepower or a charging system.

In embodiments, the buoyant vessel has a navigation system for operatingthrusters, propellers and drive system communicates with the control andmonitor system.

The following definitions are used herein:

The term “energy drive system” refers to batteries, capacitors, orcombinations thereof.

The term “fuel system” can be any fuel delivery system that operates thegenerators.

The term “generators” refers to diesel electric generators, natural gasgenerators, hydrogen fuel cells, or other types of gen sets usable infloating vessels.

The term “navigation system” refers to the controller, typically on thebridge of a buoyant vessel, that interfaces with the thrusters,generators, the master control for the drive system.

The term “propeller” can be a propeller on a drive shaft.

The term “thrusters” refers to any marine propulsion unit, including 360degree azimuthing thrusters, removable thrusters, tunnel thrusters,including non-azimuthing thrusters.

Referring now to FIG. 1, is shown a hull 1 with a drive system 10mounted within the hull 1. The hull has thrusters 2A and 2B connected tothe drive system which has a pair of generators 20A, and 20B.

The hull has a fuel system 3 connected to the generators in the drivesystem 10.

The hull or a superstructure on the hull, or an upper deck in the caseof a ferry or tug-like marine vessel has a navigation system 4electronically connected to the drive system 10 for directionallyorienting the buoyant vessel, such as by dynamic positioning.

The hull has at least one propeller 5 which can be one or more azimuththrusters for orienting the buoyant vessel, or any other type ofpropulsion system needing variable controlled power supplied.

Referring now to FIG. 2 there is shown a drive system 10 that is mountedwithin the hull of the buoyant vessel.

The drive system 10 is a comprised of a port (left) section and astarboard (right) section wherein each section may be operatedindependently or may be cross connected at several points, as needed.

Components of the port section of FIG. 2 are identical to the componentsof the starboard section and similar components are designated by thesame numeral followed by the letter “A” for the components of the portsection and letter “B” for the components of the starboard section.

Accordingly, the drive system 10 of this embodiment, includes shorepower connections 15A and 15B, generators 20A and 20B being driven bydiesel engines 9A and 9B (not shown in FIG. 2 but shown in FIG. 3),respectively, an optional AC bus 18 made up of an AC bus 18A and an ACbus 18B interconnected through a circuit breaker 19 (1600AF), rectifiers25A and 25B, battery banks 30A and 30B, two DC bus 40A and a DC bus 40Binterconnected via a switch 42 (3150 DC).

A first DC/DC converter 41A and a second DC/DC converter 41B are used.

Each DC/DC converter is in communication with a DC bus, namely DC/DCconverter 41A communicates with DC Bus 40A, DC/DC converter 41Bcommunicates with DC Bus 40B.

First energy storage system 30A can have at least one storage unit. Thefirst energy storage system 30A is in bi-directional communication withthe first DC/DC converter 41A. If there are 10 energy storage units inthe energy storage system, there are 10 DC/DC converters, one connectedto each storage unit.

Second energy storage system 30B can have at least one storage unit. Thesecond energy storage system 30B is in bi-directional communication withthe second DC/DC converter 41B. If there are 30 energy storage units inthe second energy storage system, there will be 30 DC/DC convertersneeded, one DC/DC converted connected to each storage unit

Each DC/DC converter 41A and 41B selectively controls bidirectionalcharging and discharging of each energy storage system. In embodiments,each DC/DC converter provides isolation of the energy storage systemfrom the DC bus when the energy storage system. Not all DC/DC converterswill charge and discharge have to simultaneously, there can be selectivecharging and discharging of different DC/Dc converters.

In embodiments, 2 to 10 DC bus can be used per energy storage system.

The drive system includes inverters 50A and 50B, inverter 52, inverters54A and 54B, inverters 56A and 56B, motor control centers 60A and 60B,winch motor 62, steering motors 64A and 64B, thruster motors 66A and66B, choppers 58A and 58B, grid resistors 68A and 68B, and fire pumpmotors 72A and 72B.

A DC/DC converter is for managing bidirectional control of the energyinto and out of the energy storage system.

The energy storage system with at least one storage unit is inbi-directional communication with the DC bus and the DC/DC converter.

An AC bus 18A is connected to generator 20A and shore power connection15A to receive electrical power therefrom. AC bus 18B is connected togenerator 20B and shore power connection 15B to receive electrical powertherefrom. Connections are provided as shown for generators 20A and 20BAto be connected to each other or to shore power connections 15A and 15B.

A circuit breaker 76A (600AF) and a circuit breaker 78B (3200AF) areprovided between AC bus 18A and in this example only, shore powerconnection 15A and AC bus 18A and generator 20A, respectively.Similarly, a circuit breaker 76B (600AF) and a circuit breaker 78B(3200AF) are provided between AC bus 18B and shore power connection 15Band AC bus 18B and generator 20B, respectively.

Fire pump motors 72A and 72B are connected to receive electrical powerdirectly from generators 20A and 20B, respectively, via AC bus 18A andAC bus 18B, respectively, when activated. Circuit breakers 82A and 82B(1600 AF each) are provided before fire pump motors 72A and 72B,respectively. Shore power connections 15A and 15B can also be connectedto AC bus 18A and AC bus 18B, respectively, at the generator outputs sothat shore power can run fire pump motors 72A and 72B.

Generators 20A and 20B provide 460-690 VAC (but can be higher dependingupon application, such as 4160 VAC), 45-60 Hz power and are normallyconnected individually to rectifiers 25A and 25B, respectively, whengenerators 20A and 20B are active. Generators 20A and 20B may beconnected to each other or shore power, if synchronized. Rectifiers 25Aand 25B convert alternating current (“AC”) from AC bus 18A and AC bus18B, respectively, to direct current (“DC”) which is supplied to DC bus40A and DC bus 40B, respectively. Circuit breakers 84A and 84B (3200 AFeach) are provided before rectifiers 25A and 25B, respectively.

The DC voltage from the rectifiers is used by batteries and motor loads,as described hereinafter. The DC voltage in DC bus 40A and DC bus 40B isdetermined by the batteries in battery bank 30A and 30B and their rateof charge or discharge. The rate of charge may be controlled byadjusting the output voltage of generators 20A and 20B or by the DC/DCconverters or a combination thereof.

Battery bank 30A is bi-directionally connected to DC bus 40A throughDC/DC converter 41A to receive charging current from generator 20A andother sources as hereinafter described and to provide power to DC bus40A which in turn powers DC to AC inverters 50A, 52, 54A, and 56A thatdrive motor control center 60A, winch motor 62, steering motor 64A andthruster motor 66A, respectively. DC bus 40A is also connected to achopper 58A that is coupled with a grid resistor 68A.

Inverters 50A, 52, 54A and 56A are capable of handling 100% regeneratedpower. Such power is regenerated under certain conditions primarily bythe winch when a load is dropping and the thruster when rotation isreversed. Smaller amounts of power may also be regenerated from thesteering gear or from the use of the thruster in harvesting power fromthe current. The batteries in battery bank 30A are connected toautomatically absorb regenerated power, either by displacing loadcurrent or by discharging. If the voltage in the DC bus 40A reaches acertain level, namely, about 750 volts (as adjusted for batterytemperature) chopper 58A diverts the excess regenerated power to aircooled grid resistor 68A to prevent an over voltage condition.

Battery bank 30B is bi-directionally connected to DC bus 40B throughDC/DC converter 41A to receive charging current from generator 20B andother sources as hereinafter described and to provide power to DC bus40B which in turn powers DC to AC inverters 50B, 54B, and 56B that drivemotor control center 60B, steering motor 64B and thruster motor 66B,respectively. DC bus 40B is also connected to a chopper 58B coupled witha grid resistor 68B.

Inverters 50B, 54B and 56B are capable of handling the regenerated powerfrom their corresponding loads and, more particularly, the steering gearand the thruster of the starboard section. The batteries of battery bank30B automatically absorb the regenerated power and any overloads aredirected by chopper 58B to grid resistor 68B.

Normally, DC bus 40A is supplied by battery bank 30A and DC bus 40B issupplied by battery bank 30B. DC bus 40A and DC bus 40B may be connectedso that, in the event one of battery banks 30A or 30B requires serviceor is offline, bus tie manual contactors are provided to cross feed thepower from battery bank 30A to DC bus 40B or from battery bank 30B to DCbus 40A. The contactors are manually operated and have the ability to beelectrically interlocked. They include auxiliary contacts to providetheir status information to the overall operating system.

When operating with power provided only by the batteries, each of bus DC40A and DC bus 40B is fed from its corresponding battery bank throughDC/DC converters 41A and 41B, namely, battery bank 30A and battery bank30B, respectively. The current limits of the AC drives are limited basedupon the monitored output current of the online battery bank. The DCcurrent output is monitored by means of 5000ADC rated Hal Effect Devices(“HEDs”). Set points are programmed into the operating software toprevent battery depletion beyond preset levels. In the event of eitherDC bus 40A or DC bus 40B fails, the other bus is still online due to thesplit DC bus system.

Motor control center 60A is also connected directly to AC bus 18A toautomatically draw power directly from shore power connection 15A orfrom generator 20A bypassing the batteries and electronics, if needed.Similarly, motor control center 60B is connected directly to AC bus 18Bto automatically draw power directly from shore power connection 15B orfrom generator 20B bypassing the batteries and electronics, if needed.Shore power is normally connected via shore power connections 15A and15B to motor control centers 60A and 60B so that their loads can beoperated directly, even if the batteries and inverters are out ofservice.

Shore power available from AC bus 18A and AC bus 18B can also be used tocharge batteries of battery banks 30A and 30B, respectively, throughinverters 50A and 50B, respectively. DC/DC converters 41A and 41Bprovide exact control of the battery bank boosting the input linevoltage to the higher level needed to fully charge or equalize thebatteries.

FIG. 2 shows a plurality of voltage sensors 202A and 202B for scaledvoltage feedback of the monitored energy storage units or systems whenone or more storage units of an energy storage system or one of theenergy storage systems voltage is reduced below preset level and aplurality of temperature sensors 204A, and 204B for determiningtemperature of the energy storage units.

Referring now to FIG. 3 there is shown a more detailed schematic ofdrive system 10 of FIG. 2.

FIG. 3 includes the previously described components of FIG. 2, namely,shore power connections 15A and 15B, generators 20A and 20B, AC bus 18Aand AC bus 18B, rectifiers 25A and 25B, battery banks 30A and 30B, DCbus 40A and a DC bus 40B, DC/DC converter 41A and DC/DC converter 41B,inverters 50A and 50B, inverter 52, inverters 54A and 54B, inverters 56Aand 56B, motor control centers 60A and 60B, winch motor 62, steeringmotors 64A and 64B, thruster motors 66A and 66B, choppers 58A and 58B,grid resistors 68A and 68B, and fire pump motors 72A and 72B.Furthermore, there is shown a diesel engine 9A that drives generator 20Aand a diesel engine 19B that drives generator 20B.

The control system is comprised of two redundant systems, a pilot housecontroller 102 and a drive space controller 104. Both pilot housecontroller 102 and drive space controller 104 are capable of completesystem control and monitoring independent of each other. Each of pilothouse controller 102 and drive space controller 104 has a system controlsoftware that resides in a marine rated shock proof housing chassis witha real time operating system.

The controller chassis is configured with dual independent network 106Aand 106B that provide separate control of the port and starboardcommunication networks, respectively. Networks 106A and 106B areconduits of commands and data with local subsystems.

The engine and generator controls are uniquely designed to vary the ACvoltage and the frequency as the DC bus is not adversely affected bythese changes. This operating system allows for greater utilization ofthe power input from the diesel engine generator sets by allowing theengine to ramp down the RPM in low power applications keeping the enginewithin optimal fuel efficiency conditions as the power system is notsolely dependent upon fixed frequency or fixed voltage.

The generator excitation output is strictly controlled and allows forthe generator output voltage to be increased or decreased as needed forrapid charging rates and battery output current regulation at differentrates of charge.

The engine RPM is strictly controlled and, when needed, allows for theengine RPM to fluctuate, and thus the generator output frequency to varyresulting in maximizing the efficiency of the diesel engine when loadsare beneath the 80% threshold of operation.

Referring now to both FIGS. 2 and 3, battery banks 30A and 30B areunique and can be similar units, batteries of differing chemistries orcombination of battery-capacitors each bank consisting of 320 individual2-volt batteries connected in series, series-parallel, or parallel asneeded. The DC voltage can be lower than that of the DC bus. Thebatteries are connected together via copper bus connections. The cellsare rated for 3250 ADC of short time current flow.

Each individual battery weighs 268 lbs. The total weight of each batterybank 30A and 30B is approximately 85,760 lbs. with an additional 865lbs. for the battery mounting support system.

Batteries that may be used in battery banks 30A and 30B in accordancewith the present invention are batteries manufactured by Spear, XALT,LG-Chem, Corvus, Siemens, Toshiba, Maxwell or other. Other similarbatteries may be used to form battery banks 30A and 30B.

Battery banks 30A and 30B are suitably connected to be charged bygenerators 20A and 20B, respectively. Bypasses are also provided to havebattery bank 30A charged by generator 20B and battery bank 30B chargedby generator 20A. During operation on battery power, if the batterycharge drops below a preset level, diesel engines 10A and 10Bautomatically start and provide power to the battery charging system andassist in powering the vessel. Further, appropriate connections areprovided to connect to and charge battery banks 30A and 30B by docksidepower sources through shore power connections 15A and 15B when thevessel is at the dock.

Battery banks 30A and 30B are suitably designed to be charged in bothfloat and fast charge methods from shore power or via the generatorswhile underway or by regenerative power when available to be stored.

Still referring to FIG. 3, a DC/DC converter 41A is connected to DC bus40A to receive current for charging battery bank 30A and a DC/DCconverter 41B is connected to DC bus 40B to receive current for chargingbattery bank 30B. DC/DC converters 40A and 40B are active continuouslymonitoring the state of charge of the battery banks 30A and 30B.Generators 20A and 20B are configured to charge battery banks 30A and30B or provide additional power as needed, as described below. When thepower management system (PMS) determines battery bank 30A or 30B hascrossed the preset threshold of charge, generator 20A or generator 20Bis started and brought online. After the completion of a bus 40A or bus40B active front end to supply power to the corresponding DC bus andrelieve the current load from the corresponding battery bank 30A or 30Bhas been confirmed, the PMS issues commands to DC converter 41A or 41Bto begin charging battery banks 30A or 30B. The DC/DC converters 41A and41B are deployed one per battery group thus in a configuration to enablecharge/discharge of individual groups of batteries within the batterybank as a whole.

The charging system for each battery bank 30A or 30B is designed inseparate charging groups, each group being charged at a time with adedicated DC/DC converter. When the propulsion system is active, thebattery charging system is rotated between the groups at intervalsdetermined by the state of charge of each individual battery group.

The charging requirement for the battery type is based upon voltage percell (constant voltage). The specific minimum and maximum levels ofvoltage amplitude and current flow for rates of charge are programmedinto the DC/DC converters 41A and 41B using the battery manufacture'srecommended guidelines.

The hardware for DC/DC converters 41A and 41B charging the batteries arebi-directional inverters that electrically isolate the battery from theDC bus and have the ability to increase or decrease the voltage to/fromthe battery while maintaining strict regulation of the current.Alternately, a full wave diode bridge can be used with charging currentsregulated by variance of both the generator voltage output and theengine revolutions per minute (RPM). As the vessel's service loads aresupplied power through an AC inverter assembly, these variations do notaffect the vessel's service loads.

Still referring to FIG. 3, battery monitors monitor battery banks 30Aand 30B, respectively. Battery banks 30A and 30B are monitored byincorporating voltage sensors that provide a scaled voltage feedback ofthe monitored batteries when the voltage is reduced below preset levels.The monitoring system uses the prescribed method as provided by thebattery manufacturer to determine the lowest battery in each individualbattery bank. Battery monitors identify potential problems early bytracking the voltage and temperature of each cell.

Battery monitors consist of cell monitors that measure the voltage andtemperature of individual battery cells, and a master unit that readsthe cell monitors and communicates with the system controller overnetwork communications. The master unit also reads the full cellvoltage, battery current sensors, and local ambient temperature. Analgorithm of the data may be run to determine the condition of batterybank 30A and 30B and to place limits upon the current draw allowed.

Although the system may be operated by monitoring any number of cellsfrom 1 to 1000, such as 320. In an embodiment, all 1000 cells on each ofbattery banks 30A and 30B can be monitored individually. In embodiments,every cell is monitored and data for every cell can be used to optimizebattery performance and life. Each battery monitor reads the cellvoltage and local temperature, digitizes and galvanically isolates thedata, and connects to a daisy chained serial data network connectingback to the power management system (PMS).

No individual battery cell shall be allowed depletion past 30%, thusextending the maximum power of the system delivery to the propulsionunits. If a battery draws down to or below the 50% level, generator 20Aor 20B assigned to that bus starts automatically, closes onto the mainbus and relieves the current draw from the battery bank and providescharging current to the battery bank at the same time interval. Thebattery bank charge levels are indicated on the HMI displays located inthe drive space and the pilot control.

Drive system 10 is built around battery banks 30A and 30B that serve asthe backbone of the system. The selection of the battery operatingvoltage drives the selection of the motors, generators, and drivemodules. A typical operating voltage is based upon a 480 volt system.Other systems, however, with lower or higher voltages may be used inaccordance with the present invention. If the loads and sources are notselected to be directly compatible with the battery voltage, thenadditional power conversion will be required, imposing cost, size andefficiency penalties. Therefore, system design is based upon the loadsand coordinated with the battery supply to formulate a coordinatedoperating system that is both cost effective and workable.

The following is the load voltage calculation for a 480 VAC system. Thenominal battery voltage of the Spear SMAR-6N battery used is 44.4 VDC at1500 ADC max discharge current. In this embodiment, 10 SMAR-6N's areconnected in series for 444 VDC. The minimum DC voltage needed to makeAC voltage is the peak to peak voltage times the square root of two,namely:480 VAC*1.414=>679 VDC440 VAC*1.414=>622 VDC

With 444 volts input a suitably designed electronic inverter cannotproduce the 480 VAC to the propulsion motor with only a 444 VDC inputfrom the battery bank. The DC/DC converters 41A and 41B have the abilityto increase the DC voltage from the battery banks 30A and 30B to matchthat of the DC bus 40A and 40B. Therefore, with the capability of theDC/DC converters to match DC voltage on either side the system asdeployed has increased optimal operation as minor variances of thevoltages do not adversely affect the battery banks or the either DC bus.

The following is the line voltage calculation. The SMAR-6N batterycharging voltage is 492 DC volts (49.2-V/cell), @ 450 DC amps under fastcharge conditions. As the DC/DC converter has the ability to increase ordecrease the voltage on either side of the converter (battery banks30A-30B or DC bus 40A and DC bus 40B) the strict voltage regulation ofthe system as seen with other systems is eliminated thus providing apower system more easily strictly controlled within exact parametersneeded for long term trouble free operation.

By these calculations, under load a 480 volt source will closely matchthe nominal battery voltage, under any operational circumstances whenthe state of charge is maintained within the manufacture's recommendedguidelines.

The level of boost is readily provided by inverters 50A and 50B run withreverse power flow, so that those inverters can serve double duty asbattery chargers when operating from shore power through shore powerconnections 15A and 15B.

Diesel engines 10A and 10B are similar units, each having a minimum KWrating of 1800 KW. Diesel engines 10A and 10B are suitably designed tomeet and/or exceed EPA Tier mandated emissions throughout the range ofloaded conditions. Diesel engines 10A and 10B are suitably rated tomarine use as stipulated by the American Bureau of Shipping (“ABS”)requirements and suitably designed to utilize marine heat exchangers forthe primary method of cooling. Diesel fuel requirement is standard andthus, diesel engines 10A and 10B can be fueled at any standard supplierof diesel fuels along the coastal waterways.

Diesel engines 10A and 10B have local engine monitoring functionscomplete with electronic capability to communicate with the vessel PowerManagement System (“PMS”) via serial connection.

Diesel engines 10A and 10B provide mechanical power to rotate generators20A and 20B, respectively, at a set speed. Generators 20A and 20Bconvert the mechanical energy into electrical energy usable by thevessels systems.

Generators 20A and 20B which are similar units are suitable designed for460-690 VAC, 2500 kVA, 45-60 Hz electrical requirements. They havewinding and bearing temperature monitoring devices to satisfy AmericanBureau of Shipping (“ABS”) marine propulsion power system requirement.These devices are 100 ohm platinum RTD's.

Any commercially available diesel engines and generators meeting thestated specifications may be used as diesel engines 10A and 10B andgenerators 20A and 20B. A preferred diesel engine/generator package isthe Marine Caterpillar Model 3516 DITA Direct Injection Turbochargedwhich is after cooled with a separate circuit after cooling. Thepreferred generator 20A and 20B is a Kato or equivalent 480 VAC, 60 Hzgenerator. This offshore electric diesel engine/generator with a ratingof 1825 KW @ 1800 RPM includes the following standard attachments:

Air Inlet System (after cooler core (corrosion resistant), air cleaner(regular duty with soot filter), service indicators)

Control System (Caterpillar ADEM Electronic Engine Control (left hand),requires 24V DC 10 Amp continuous, 20 AMP intermittent, clean electricalpower).

Heat Exchanger Cooled Marine (Outlet controlled thermostat and housing,jacket water pump gear driven, single outlet with tubed heat exchanger,gear driven centrifugal after cooler fresh water cooling pump (SCAC),SCAC pump circuit contains a thermostat to keep the after cooler coolantfrom falling below 30 deg C. (85 F)).

Exhaust System (standard stroke exhaust fittings (flexible 203 mm (8in)), standard stroke exhaust flange (welded 356 mm (14 in), dry gastight exhaust manifolds with thermo-laminated heat shields, dualturbochargers and thermo-laminated heat shields).

Flywheels and Flywheel Housings (flywheel (SAE No. 00 with 183 teeth),flywheel housing (SAE No. 00), SAE standard rotation).

Fuel System (fuel filter (left hand), fuel transfer pump, flexible fuellines, fuel priming pump (left hand), electronically controlled unitinjectors).

Instrumentation (electronic instrument panel (left hand); analog gaugeswith digital display data for engine oil pressure gauge, engine watertemperature gauge, fuel pressure gauge, system DC voltage gauge, airinlet restriction gauge, exhaust temperature (prior to turbochargers)gauge, fuel filter differential pressure gauge, oil filter differentialpressure gauge, service meter (digital display only), tachometer(digital display only), instantaneous fuel consumption (digital displayonly), total fuel consumed (digital display only), and engine start-stop(off, auto start, manual start, cool down timer))

Lube System (crankcase breather, oil cooler, oil filter (left hand),deep oil pan, oil pan drain valve (2″ NPT female connection),lubricating oil (SAE 10W30, Caterpillar DEO (CG4) 813 L)).

Mounting System (rails, mounting, floor type, 254 mm (10 in)).

Power Take-offs (accessory drives, upper right hand, lower left handFront (available for PTO usage), front housing (two-sided)).

Starting System (air pre lube pump, air starting motor (right hand, 620to 1034 kPa (90 to 150 psi), left hand control), air silencer).

General (paint (caterpillar yellow), vibration damper and guard, liftingeyes).

Fuel Cooler. One Young Touchstone Remote vertical fuel cooler withhorizontal discharge is installed. Radiator is sized to cool up to five3516B engines manifolded together or standard marine heat exchangers maybe used as room permits. It Includes Heresite coated core and hot dippedgalvanized steel parts, 5 HP TEXP motor (3 ph/230/460 volt) and core andfan guards.

Protection System. ADEM or any other equivalent monitoring systemprovides engine de-ration, alarm, or shutdown strategies to protectagainst adverse operating conditions. Selected parameters are customerprogrammable. Status available on engine mounted instrument panel andcan be broadcast through the optional customer communications module orprogrammable relay control modules(s)). Initially it is set as follows:

Safety Shutoff Protection, Electrical (oil pressure, water temperature,overspeed, crankcase pressure, after cooler temperature; includes airinlet shutoff, activated on overspend or emergency stop).

Alarms, Electrical alarms can be (ECM voltage, oil pressure, watertemperature (low and high), overspend, crankcase pressure, after coolertemperature low water level (sensor is optional attachment), air inletrestriction, exhaust stack temperature, filter differential pressure(oil and fuel)).

Derate, electrical can be (high water temperature, crankcase pressure,after cooler temperature, air inlet restriction, altitude, exhausttemperature; emergency stop push button, located on instrument panel;alarm switches (oil pressure and water temperature), for connection toalarm panel).

Each diesel engine 10A/generator 20A set and diesel engine 10A/generator20B set includes a control cubicle for load sharing control. Eachcontrol cubicle includes the following: 3200 amp rack out main breakerwith LSI adjustable trip, under voltage trip and trip indicator;3×4500:5 current transformers; 1 load sharing speed control unit foractive KW and KVAR load sharing control of the engine and generator set(controller includes protections for under voltage, over voltage, overfrequency, under frequency and reverse power; AC module controltransformer; sync control transformer and Auto Sync controls; excitationpower transformer; engine OFF/IDLE/RUN switch; generator sync selectorswitch; interlocked breaker close push button; digital screen displaypower management meter for display of 3 phase voltage, 3 phase amperage,frequency, Kilowatts, Kilovars, bus harmonics and voltage fluctuationand record trending of up to 3 years accumulative engine/generator loadand fault data; RTD generator temperature display for winding 1, winding2, winding 3, drive bearing and tail bearing; power limit interface withAC drives and battery demand monitor; hour meter indicating hoursonline; generator run light; generator online light; emergency shutdowninterface relay; generator heater relay; no touch control fuses; marinenonconductive handrails; marine drip shield IP20; engine/generator fieldconnection terminal block; AC Bus ground fault indication

Still referring to FIGS. 2 and 3, each of inverters 50A, 50B, 52, 54A,54B, 56A and 56 B and choppers 58A and 58B consist of a plurality ofmodules, preferably, TeraTorq™ Inverter Modules (TIM-200) or equivalentmanufacture. Each module can drive 300 HP and can be configured inreal-time for a number of different modes of operation. The TIM-200modules are 28 inches deep 6 inches wide and 13 inches high. All of thehigh power connections are blind-mate connectors in the back so themodules can be replaced without handling dangerous bus voltages. ATIM-200 module has blind mate power connections, AC & DC fuses, IGBTswitches, 32 Bit DSP controls and liquid cooling connections. Blind matepower connections are suitable for removing and replacing a particularmodule without touching the power conductors. AC & DC fuses are includedin every power lead whereby any problem that may occur in a particularmodule is isolated in the particular module without affecting the othermodules. The IGBT switches are 1700 volt switches that providesufficient margin for unexpected events. The 32 bit DSP controls is abuilt in 32 bit 150 MHz digital signal processor that enables aparticular module to respond instantly and correctly to changingvoltages, currents and temperatures. Liquid cooling connections providefor the flow of high performance heat sink liquid that removes heat formthe IGBT switches of the module. Each module has digital status readout.

A plurality of modules is inserted in a cabinet with the cooling andcommunication bus connections allowing for the easy access, removal andinsertion of each module.

Still referring to FIGS. 2 and 3, each of inverters 50A and 50B has 2TIM-200, or equivalent, drive modules (4 modules total) and provide 60Hz 440 VAC power for distribution through a motor control center. Thepower is 250 kW and the current is 400 A. Inverters 50A and 50B are alsoback driven to provide DC power for battery charging when on shorepower.

Inverter 52 has 1 TIM-200, or equivalent module and providesfour-quadrant variable speed control to a 150 kW induction motor,voltage 440 VAC and current 200 A. Other inverters may be used as longas special modifications are made to the firmware to ensure that the DCbus voltage can be operated at a large differential (200 vdc-1000 vdc)without faulting.

Each of inverters 54A and 54B has 1 TIM-200 module or equivalent, (2modules total) and provides four-quadrant variable speed control toinduction motors totaling 100 kW, current 150 A and 440 VAC.

Still referring to FIGS. 2 and 3, inverters 54A and 54B have 15 TIM-200modules, or equivalent, each. They each provide four-quadrant variablespeed control to a 2500 kW induction motor, current 3000 A, 440 VAC.

Each of choppers 58A and 58B (600 kW, 800 A, 750 VDC, 2 TIM-200 modules,or equivalent, each) handle excess electric power from the thrusters andwinch when they regenerate power. Each of choppers 58A and 58B sends anyunusable electric power to external load resistors 68A and 68B,respectively, to be dissipated.

Drive system 10 includes two drive cabinets (one for the port sectionand the other for the starboard section). Drive cabinet contains thecoolant, control, and power connections for the system. It is arrangedas a grid, with each the modules for each subsystem typically installedside by side on a single row, or multiple rows for higher power devices.Each of the two cabinets requires 55 gallons per minute of liquidcoolant (110 GPM total).

Referring now to FIG. 2, AC bus 18A and AC bus 18B is assembled as asingular bus system and it supplies power to battery charging systems92A and 92B, fire pump motors 72A and 72 b and the charging systems ofDC Bus 18A and DC bus 18B.

All power breakers connected to AC bus 18A and AC bus 18B have thecapability for remote closure and remote disconnect. The status of thebreaker is also monitored by the PMS automation and provides operatingstatus and interlock functionality.

The main bus and marine switchgear is designed with the followingstandards: main bus rating of 5500 amps for ac bus distribution; busfault rating is 100 KIA @ 480 VAC; main bus is plated copper; main bushardware is stainless grade 8 hardware

Switchgear construction is welded steel frame with 12 gauge hingeddoors; all cubicles requiring forced air ventilation have louvered ventswith filtered suction; all breakers are rack out marine type as perrequirement; all breakers have network communications capability; allbreakers with ratings greater than 600 amps supplied with auto chargingcontrols for stored energy devices and remoter close solenoids; shorepower breaker is interlocked with the generator breakers; status of mainbus and interlock condition is indicated by visual indicator (light);all breaker nomenclature to include breaker setting information, load orsource information and component reference id; local and remote groundfault indications; nonconductive hand rails as per abs requirement; dripshields as per ABS requirement; paint requirement is ASA 61 Polane B orequivalent coating system; and a 15 inch color touch screen centrallylocated in the switchgear for ease of monitoring system status and/oralarm conditions; generator temperature resistive thermal device aretied into power management system alarm system with set points as permanufacture specifications; engine generator control system hasauto/off/manual mode selection for maintenance purposes; fire pumpcontrols to include soft start system to reduce magnetizing currentthroughput when starting motors. Soft starters are complete with bypasscontactors; and all status indication lights located on front doors are24 volt with exception of generator status lights on generator controlcubicle doors.

Still referring to FIG. 2, circuit breakers 76A and 76B are SiemensWL1000AF, rack out marine use (or equivalent); 600A rating plug, LSIelectronic trip unit; 120 VAC motor charging unit; 120 VAC remote closecoil; 120 VAC under voltage trip unit, network communications option; 3sets NO contacts; 3 sets NC contacts.

Circuit breakers 78A and 78B are Siemens WL3200AF, rack out marine use(or equivalent); 3200A rating plug, LSI adjustable electronic trip unit;120 VAC motor charging unit; 120 VAC remote close coil; 120 VAC undervoltage trip unit, network communications option; 3 sets NO contacts; 3sets NC contacts.

Circuit breakers 82A and 82B are Siemens WL1600AF, rack out marine use(or equivalent); 1600A rating plug, LSI adjustable electronic trip unit;120 VAC motor charging unit; 120 VAC remote close coil; 120 VAC undervoltage trip unit, network communications option; 3 sets NO contacts; 3sets NC contacts.

Circuit breakers 84A and 84B are Siemens WL3200AF, rack out marine use(or equivalent); 2500A rating plug, LSI adjustable electronic trip unit;120 VAC motor charging unit; 120 VAC remote close coil; 120 VAC undervoltage trip unit, network communications option; 3 sets NO contacts; 3sets NC contacts.

Referring now to FIG. 3, breakers 98A and 98 b for charging systems 92Aand 92B are shown. Breakers 98A and 98B are Siemens WL1000AF, rack outmarine use (or equivalent); 1000 A rating plug, LSI adjustableelectronic trip unit; 120 VAC motor charging unit; 120 VAC remote closecoil; 120 VAC under voltage trip unit, network communications option; 3sets NO contacts; 3 sets NC contacts.

Referring now to FIG. 4, there is shown system control 100 for thebuoyant vessel with controlling and monitoring drive system 10.

Control system 100 is formed of two redundant systems, a pilot housecontroller 102 and a drive space controller 104. Both pilot housecontroller 102 and drive space controller 104 are capable of completesystem control and monitoring independent of each other. Each of pilothouse controller 102 and drive space controller 104 has a system controlsoftware that resides in a marine rated shock proof housing chassis witha real time operating system.

The controller chassis is configured with dual independent network 106Aand 106B that provide separate control of the port and starboardcommunication networks, respectively. Network 106A is the conduit ofcommands and data with local subsystems in the port communicationsnetwork including a controller 108A for generator 20A, a monitor 110Afor battery bank 30A, DC/DC converter 41A, a first controller 112A for afirst subsystem 113A for inverters 50A, 52, 54A and chopper 58A, asecond controller 114A for a second subsystem 115A for inverter 56A, acircuit breaker 116A, a first motor starter 118A, a circuit breaker 120Aand a second motor starter 122A. Some of the subsystems are simplemonitors that only report data (for example the battery voltage monitorsand circuit breaker status monitors). Other subsystems receive andexecute commands as well as reporting data (for example the motorcontrollers and the generator controls). The inverter drive subsystemshave an additional level of control network. Commands and data areexchanged with the system controller over the network, and the localcontroller coordinates the operation of inverter modules.

Similarly, network 106B is the conduit of commands and data with localsubsystems in the starboard communications network including acontroller 108B for generator 20B, a monitor 110B for battery bank 30B,DC/DC converter 41B, a controller 112B for a subsystem 113B forinverters 50B, 54B and chopper 58B, a controller 114B for a subsystem115B for inverter 56B, a circuit breaker 116B, a motor starter 118B, acircuit breaker 120B and a motor starter 122B. Like in the port network,some of the subsystems of the starboard network are simple monitors thatonly report data (for example the battery voltage monitors and circuitbreaker status monitors). Other subsystems receive and execute commandsas well as reporting data (for example the motor controllers and thegenerator controls). The inverter drive subsystems have an additionallevel of control network. Commands and data are exchanged with thesystem controller over the network, and the local controller coordinatesthe operation of inverter modules.

For the buoyant vessel, control system 100 provides reliable andresponsive operation of all of the elements of the power system througha simple and redundant operator interface. Primary control is performedfrom the pilot house where pilot house controller 102 is controllerusing pilot house manual controls 130, such as switches, knobs, levers,and joysticks, at the left edge of the diagram. Clear visual feedback ofpropeller speed can be provided on two dial gauges. Pilot house manualcontrols 130 are supplemented by a touch screen computer display 132.Touch screen computer display 132 provides detailed operating statusinformation. A graphical user interface lets the operator select thedata to be displayed, change operating modes and limits, and acknowledgestatus messages. The underlying philosophy is that time-critical andfrequently used controls have dedicated manual inputs, and the rest areaccessed through the touch screen.

The buoyant vessel has pilot house manual controls 130 and pilot housetouch screen monitor 132 are connected to pilot house control 102, whichis a modular controller chassis running a real time operating system.This unit contains the control and interlock programming thatcoordinates system operation. It communicates with the power systemcomponents over the two separate networks 106A and 106B.

The redundant set of controls drive space 104 is located in the drivespace of the vessel and is connected to drive space manual controls 140similar to pilot house manual control 130 and drive space touch screenmonitor 142 similar to pilot house touch screen monitor 132. Drive spacecontroller 104 provides local monitoring and display of system status,but only exerts control if assigned by the pilot house or if pilot housecontroller 102 is offline. This architecture provides a high degree ofprotection because each of the independent communication networks can beindependently controlled by two physically separate control stations.

In a typical configuration, the control system and hardwareconfiguration has the safety features designed into the system. Thesafety functions are broken into specific hardware and/or operatingfunction groups. Examples of such safety functions include thefollowing:

SAFETY FUNCTION ACTION Reverse Power Trip Breaker-Engine Shut down OverSpeed Trip Breaker-Engine Shut down Under Voltage Trip Breaker OverVoltage Trip Breaker Generator Over Temp Alarm Synchronization CheckBreaker Closure Control Permissive Ground Fault Alarm DC Bus 40A FaultAlarm - Shutdown DC Bus 40B Fault Alarm - Shutdown Charging Unit 92AFault Alarm - Reduction output Battery Bank 30A Charging Unit 92bB FaultAlarm - Reduction output Battery Bank B Propulsion Motor OvertempAlarm - Shut Propulsion Motor

The control system and hardware configuration of drive system 10 hasseveral interlock functions suitable for the operation of drive system10. Such interlock functions include the following:

Shore Power Breaker interlocked with Energized Bus Sensor. Shore PowerBreaker cannot be closed with AC Bus 18 energized or Generator 20A orGenerator 20B breaker closed.

Battery Banks 20A and 20B—Tie manual DC contactor switches. Logicstatement is as follows;

A=1, B=1, T=0

A=0, B=1, T=0 OR 1

A=1, B=0, T=0 OR 1

Battery fault 30A or 30B shutdown of DC/DC converter 41A or 41Bprotective function.

Fire Pumps Disabled unless FIRE FIGHTING Mode selected.

Main Propulsion Drives not enabled unless permissive received from auxfunction enable circuit (Thrustmaster System or Equivalent).

AC/DC Converters 25A & 25B cannot be enabled if DC Bus 40 fault exists.

Port MCC drive feed interlocked with backup 480 VAC Bus feed breaker.Normal operation is from AC drive inverter supply. Back emergencyfailure mode is fed from 480-volt bus.

Starboard MCC drive feed interlocked with backup 480 VAC Bus feedbreaker. Normal operation is from AC drive inverter supply. Backemergency failure mode is fed from 480-volt bus.

Drive system 10 and the vessel utilizing drive system 10 areappropriately designed to operate in three different modes, namely, thegreen mode, the tow mode and the firefighting mode. Green mode is thedefault mode of operation. The operator can select either tow mode orfirefighting mode to override some of the automatic power managementfunctions of the control system.

In the green mode the vessel is supplied power only by the batteries inbattery banks 30A and 30B without utilizing the diesel engines for shippropulsion and/or ship service.

Control system 100 energizes diesel engines 10A and 10B and generatorsonly when needed to provide peak power or battery charging. Thebatteries in battery banks 30A and 30B hold enough energy to sustain 300Hp of incidental loads for over 8 hours between charges; however batterylife is increased if more shallow discharge cycles are used. Generators20A and 20B come on line automatically based on a combination of theload and the battery state of charge. In the green mode, the minimal useof diesel engines cause substantial reduction in noise level, energyconsumption and carbon emissions. Green mode is designed for operatingthe tugboat between locations when it is not towing another vessel andfor dockside operations.

The tow mode may be manually selected by the operator. Selecting towmode energizes diesel engines 10A and 10B and generators 20A and 20B sothat they will be available immediately to support peak power demands.The voltage from generators 20A and 20B maintains a float charge onbattery banks 30A and 30B except at very heavy loads, where power isdrawn from battery banks 30A and 30B to supplement generators 20A and20B.

The firefighting mode may be manually selected by the operator.Firefighting mode energizes both diesel engines 10A and 10B andgenerators 20A and 20B, and gives priority to the fire pumps that aredriven by fire pump motors 72A and 72B. The power available tononessential systems is limited in this mode. The fire pumps receive ACpower directly from generators 20A and 20B, and are not dependent onbattery banks 30A and 30B or power conversion electronics.

The drive system operating modes differ in the sources of power and thepath that the power takes to the load. Each of the vessel operatingmodes may include several different drive operating modes. In normaloperation the control system automatically selects the drive systemoperating mode; however in some cases the operator may directly selectthe operating mode for maintenance or emergency conditions. For example,the maintenance schedule might call for battery equalization to be runonce every six months. The port and starboard sides of the drive systemmay be in the same or different modes at any time.

If the vessel is in green mode, there is sufficient charge in batterybanks 30A and 30 b, and the load is not too heavy, the drive system willrun on battery power. At no load and full charge the battery voltagewill be 444 volts DC. At 500 Horsepower total load the voltage will showa relatively modest droop. The system could be run under this conditionfor over five hours from fully charged batteries; however startingdiesel engines 10A and 10B and generators 20A and 20B periodically willincrease the service life of battery banks 30A and 30B by removing load(current draw) from battery banks 30A and 30B and providing chargingcurrent, which will be proportional to the overall system load.

An analysis determines the optimal generator starting scenarios. Forexample, at 90% state of charge the diesels might be programmed to comeon at a load equal to 25% of the one-hour discharge current, and 10%current at 75% state of charge. The goal of the optimization is tominimize pollution and fuel use, while maximizing service life.

When operating from battery power there is no voltage on the AC bus 18coming in to rectifiers 25A and 25B. All AC power for the MCCs and motorloads is synthesized from battery voltage from DC Bus 40A and DC bus 40Bby the inverters. The battery state of charge is calculated by measuringthe battery cell voltage, temperature, and load current using networkedintegrated circuit boards attached to the batteries.

When generators 20A and 20B are brought on line they feed AC power torectifiers 25A and 25B, which in turn provide DC power to battery banks30A and 30B and inverters. If the AC voltage is low the rectifier outputwill be too low to feed power into DC bus 40, and the system willcontinue to run from battery power. As the AC voltage is increased, therectifier will start to take load off of the batteries, causing thebattery terminal voltage to increase. If the AC voltage is increasedfurther, the rectifier will provide all of the load current to theinverters and will also provide current to recharge the batteries. Thepower output of the generators and the charging rate of the batteriescan be controlled by varying the DC/DC converter voltage over a fairlynarrow range. This concept is unique in that the excitation level isvaried due to the charging rate needed for the battery bank. Theexcitation has limits placed upon it so not to exceed the maximum limitsof the battery manufacture recommendations.

The applied charging voltage is automatically adjusted by the DC/DCconverter for battery operating temperature, and the charging current islimited to avoid excess heating. Also, over-charging must be avoidedbecause it can lead to gas discharge or thermal runaway. For thisreason, it is very important that the proper manufacture battery data beused to program the operating parameters of the DC/DC converters 41A and41B.

As in battery power mode, when generators 20A and 20 b are on, all ACvoltages for the MCCs and motor loads are synthesized from DC voltage bythe inverters. However, AC power from generators 20A and 20B isavailable to the fire pumps connected directly to the 480 volt Bus inthis mode. Generators 20A and 20B can be run separately to regulatebattery banks 30A and 30B independently, or the AC bus 40A and AC bus40B can be cross connected to charge both battery banks from a singlegenerator or a pair of synchronized generators. When operating in thismode the generator VAR sharing circuits are synchronized to providecurrent from the same amplitude of current from each generator.

When the vessel is connected to 480 volt shore power via shore powerconnections 15A and 15B, battery banks 30A and 30B can be charged andloads can be run without powering generators 20A and 20B. The preferredconnection for shore power is directly into the port and starboard MCCs.With this configuration MCC loads can be run even if the driveelectronics or batteries are disabled for maintenance.

Battery charge regulation is provided by inverters 50A and 50B thatnormally synthesize MCC power from the battery voltage. They operate asboost rectifiers to provide the proper charging voltage for batterybanks 30A and 30B. At room temperature the battery voltage is regulatedto 444 volts to maintain a float charge. At higher temperature thevoltage is reduced.

Shore power can also be connected to AC bus 18 at the generators. Thisallows the fire pumps to be operated, and allows charging of batterybanks 30A and 30B through rectifiers 25A and 25B. It should be noted,however, that only a low level of charge is possible through this pathunless the incoming voltage exceeds 480 volts.

A variety of maintenance modes are available to deal with unusualsituations. For example, bypass circuits allow the MCCs to be connecteddirectly to the output of generators 20A and 20B, or allow the firepumps to operate from the MCCs. Both battery banks 30A and 30B can becharged from a single generator 20A or 20B. The port and starboardinverters can be cross connected to operate from a single battery bank30A or 30B. By providing such designs, when a failure occurs in thesystem, such failure causes only a partial and not a total disablementof the vessel thereby allowing the vessel to operate.

The use of the combination of battery banks 30A and 30B and generators20A and 20B allows for reduction of use of generators 20A and 20B incertain operating modes and, more particularly, in the green mode. Thebattery output from battery banks 30A and 30B is connected to DC bus 40that provides power to the AC drives which are electronically controlledand provide power to the thrusters and all ships service. The tugboathas the ability to be mobilized without the need to operate generators20A and 20B and can operate for prolonged periods on battery poweralone. Generators 20A and 20B are only used in the towing mode, firefighting mode or when charging the batteries. As a result, fuelconsumption is reduced thereby reducing fuel costs and carbon emissionsfrom the vessel. It is estimated that carbon emissions are reduced by asmuch as 90 percent as compared to the previous designs of tugboats andoperations.

In drive system 10, power may be drawn from generators 20A and 20B,shore power connections 15A and 15B, or battery banks 30A and 30B. Powermay be drawn by large loads, such as the thrusters, steering, winch, andbattery, or by smaller loads attached to the motor control centers.System efficiency is maximized by streamlining the paths among the loadsand sources, and by ensuring seamless transitions as conditions change.

The control system of drive system 10 is configured to draw energy fromthe most efficient source. In addition the system supports re-generationto channel energy from the drive back into battery banks 30A and 30Bunder certain conditions as previously described.

The replacement of diesel engines and generators with battery banks 30Aand 30B reduces the size of the drive line and the overall spacerequired for it. It is estimated that the space is about 50% smallerthan that required for other commercial drives.

The use of a set of identical modules TIM-200, or equivalent, allows fortheir replacement at sea without an electrician and results in reductionof down time and maintenance costs. Modules are automaticallyre-programmed for the specific application and can be swapped at sea.For example, the winch drive requires a single module while eachthruster uses 15 modules. If a winch drive module fails, it can bereplaced by one of the thruster modules and while the maximum thrusterpower would be limited slightly, the winch would be fully operational.

For the buoyant vessel, the drive system 10 is designed to comply withthe design and manufacture specifications of the American Bureau ofShipping as found in the Rules for Steel Vessels 2019, and subsequentamended documents with regard to ABS manufacturing rules for steelvessels of this class with special emphasis on redundancy and emergencymode requirements.

The buoyant vessel and system is controlled by standard software thatare available with the components of the system. The software issuitably programmed to control the operation as described herein.

The operating system design of the marine hybrid propulsion systemallows for the buoyant vessel to make way without the need to operateany diesel engines. This is considered unique as no other system hasthis ability. The unique design features are described below.

The control system allows for vessel to be under way without the needfor diesel engine power source to be online. This is unique to thebuoyant vessel operating system from all other propulsion controlsystems. The result is a dramatic fuel reduction usage due to therequirement that no prime movers are needed for propulsion and shipsservice power, carbon emissions are inherently reduced for the samereason plus a dramatic reduction in baseline ambient noise of the vesselin operations. All three of these areas are beneficial to harboroperations for tug boats and ferries.

Battery system charge can be refreshed rapidly by precise control ofengine (prime mover) RPM and generator voltage output (due to thevariable excitation control system) or simply with the DC/DC converterwithout affecting the power output control capability of the propulsionsystem or the vessel service supplies. During rapid refresh the neededpower output from the controlled power output devices are constant andconsistent with the power needed for any specific purpose.

In any mode of operations, the hull of the buoyant vessel has inertialstored energy can be harvested with reduction of vessel speed commandsand returned to the energy storage system (battery banks) by theautomated electronic control system or the energy can be placed into thevessel ships service system. This structure maximizes overall powersystem efficiency by harvesting a ship's hull inertial energy andsubsequent conversion to a usable source energy.

Power is supplied to the buoyant vessel by one of three most efficientsources as defined by the buoyant vessel's automated vessel powermanagement system. The three (3) sources of power are: (a) Stored energybattery supply power source, which depending upon the system design isbetween 1.5 megawatt to 10 megawatts; (b) Diesel engine generator powersource; and (c) Shore power source when connected dockside.

In the latter case, the stored energy charging system and the vessel'sservice power used are transferred to the most efficient source which islocated at the power generation plant. Typically power generation plantsare regulated thereby limiting the total amount of carbon emissionsallowed per kilowatt hour of power generated.

Battery storage and power delivery system is managed on a “per cell” anda “per group” basis. This energy storage allows for very efficient powermanagement into and out of the battery energy storage system.

The buoyant vessel control system is designed with a green mode ofvessel operations unique to the system operating system design. Aspreviously stated, this invention allows the buoyant vessel to make way(propulsion systems and ships service systems active) without the needto have diesel engines operating, resulting in reduced carbon fuelconsumption and the resultant reduced carbon emissions.

The green mode of operations also allows for reduced sound decibellevels during operations, which benefits local populations and thepersonnel operating the buoyant vessel onboard.

The power draw from the energy storage system is electronicallymonitored and controlled by the unique control system design in thefollowing method and results: (a) the stored energy is calculated andthe energy drawdown is electronically controlled based upon the totalavailable energy calculation of the stored energy battery system; (b)the AC propulsion drive current limits are continuously monitored andadjusted and so the propulsion system efficiency is considered duringoperation to maximize total system efficiency. This is seamless to thevessel operator and comparable to the fly by wire operation of air craftand modern automobiles; and (c) by slowing the buoyant vessel downduring green mode the energy from the buoyant vessel is harvested by thepermanent magnetic propulsion motors and delivered back to the energystorage system or to the ships service power system. Either way, thereis a reduction of energy draw from the energy storage system thusmaximizing efficiency of the overall power system.

Buoyant vessel automated power management allows for dramatic drop in DCbus voltage in emergency vessel operating conditions. These conditionsare defined as the vessel being underway and the use of diesel enginepower generating plants are lost (for whatever reason, mechanicalproblems, loss of fuel supply, etc.). The AC drive operating algorithmsallow for a wide range of DC bus fluctuations which allow for large drawdown in power from the energy storage battery banks in emergencyoperating states as defined. This is unique to the system operatingdesign and allows for true emergency mode operation.

Sufficient warnings to the operator by the vessel control automationsystem are provided to alert the operator to adverse equipmentconditions. These include the cell by cell monitoring of the energystorage system (batteries), therefore the operating system providesadvance notice of any potential adverse equipment condition. The batterycell monitor produces an alarm condition if the cells have adifferential voltage in excess of 1 volt DC. The battery monitoringsystem senses, displays and records the temperature of each individualbattery cell. The operating system is programmed to predict a cellfailure in advance.

While these embodiments have been described with emphasis on theembodiments, it should be understood that within the scope of theappended claims, the embodiments might be practiced other than asspecifically described herein.

What is claimed is:
 1. A drive system mounted to a hull of a buoyantvessel for balancing power between electrical devices on the buoyantvessel using a digital signal processor that enables a particular moduleto respond instantly and correctly to changing voltages, currents,temperatures, thrusters and propellers of the buoyant vessel, the drivesystem comprises: (a) a rectifier for converting AC current to DCcurrent; (b) a generator connected to the rectifier; (c) an AC bus incommunication the rectifier; (d) a DC bus in communication with therectifier; (e) a DC/DC converter in communication with the DC bus; (f)at least one energy storage system with at least one storage unit inbi-directional communication with the DC/DC converter; wherein the DC/DCconverter selectively controls bidirectional charging and discharging ofthe at least one energy storage system and, wherein the energy storagesystem comprises at least one of: a battery, a battery-ultra capacitor,an ultracapacitor, and capacitors; (g) an inverter in communication withthe DC bus; (h) a prime mover; (i) a load regenerating device connectedto the inverter, wherein the rectifier is configured to provideregenerated power from the prime mover, load regenerating device, orcombinations thereof to the energy storage system; and (j) a control andmonitor system in communication with the DC/DC converter, one or morestorage units of the at least one energy storage system, the generator;and wherein the control and monitor system has predefined specificationsfor at least one of: storage units of at least one energy storagesystem; stored therein and wherein the control and monitor system isadapted to: a. automatically controls the DC/DC converter when one ormore storage units of an energy storage system or one of the energystorage systems falls below a predetermined load, or the charge level ofone or more of the storage units of an energy storage system or one ofthe energy storage systems is depleted past a preset limit of the chargelevel thereof; b. automatically relieves a current draw from one or morestorage units of an energy storage system or one of the energy storagesystems; c. automatically provides charging current to the one or morestorage units of an energy storage system or one of the energy storagesystems; and d. automatically draw power from at least one of the loadregenerating device and the generator, and redirect energy from at leastone of the load regenerating device and the generator to the DC/DCconverter and then to one or more storage units of an energy storagesystem or to an energy storage systems.
 2. The drive system of claim 1,wherein the control and monitor system has predefined specifications forat least one of: storage units of at least one energy storage system andat least one energy storage system, and wherein the control and monitorsystem is adapted to: monitor at least one of: the storage units of atleast one energy storage system and to automatically start the primemover.
 3. The drive system of claim 1, wherein the control and monitorsystem has predefined specifications for at least one of: storage unitsof at least one energy storage system, and at least one energy storagesystem; and wherein the control and monitor system is adapted to:control the DC/DC converters to ensure one or more storage units of anenergy-storage system or one or more energy storage systems are notovercharged.
 4. The drive system of claim 1, comprising a plurality ofvoltage sensors for scaled voltage feedback of the monitored energystorage units or systems when one or more storage units of an energystorage system or one of the energy storage systems voltage is reducedbelow preset level and a plurality of temperature sensors fordetermining temperature of the energy storage units.
 5. The drive systemof claim 3, wherein the control monitor unit reads the plurality ofvoltage sensors, the plurality of temperature sensors, the thruster loadand the propeller load.
 6. The drive system of claim 3, wherein thecontrol and monitor system is configured to monitor and control the DCto DC converter levels to control a charging rate of the one or morestorage units of an energy storage system or one of the energy storagesystems.
 7. The drive system of claim 1, wherein the load regeneratingdevice is a winch motor, steering motors, thruster motors, propellermotor, fire pump motors, motor control centers, or combinations thereof.8. The drive system of claim 6, wherein the control and monitor systemprevents generator excitation levels from exceeding a maximum excitationlevel of the DC bus.
 9. The drive system of claim 1, wherein the DC busin communication with the rectifier is at least one: a split DC bus or anon-split DC bus.
 10. The drive system of claim 1, comprising from 2 to10 DC bus.
 11. The drive system of claim 1, further comprising a chopperconnected to a resistor for dissipating excess power if one or morestorage units or one or more energy storage systems are offline or fullof power.
 12. The drive system of claim 1, further comprising from 1inverter to 50 inverters.
 13. The drive system of claim 1, wherein thecontrol and monitor system comprises a communication network.
 14. Thedrive system of claim 13, wherein the communication network is at leastone of: a global communication network, a local communication network, acellular communication network, the internet, and a satellitecommunication network.
 15. The drive system of claim 1, wherein thegenerator and the prime mover can be variable speed, and wherein thegenerator is variable voltage to control fuel efficiency.
 16. The drivesystem of claim 1, wherein each AC bus is in electrical communicationwith shore power or a charging system.
 17. The drive system of claim 1,wherein a navigation system for operating thrusters, propellers anddrive system communicates with the control and monitor system.